This disclosure provides a method for introducing a bandgap in single layer graphite (graphene) on a SiO2 substrate, while also allowing for independent control of the majority carrier type via surface adsorbates. Specific applications of the invention include patterning graphene samples for nanocircuit design and device integration at various scales, for example, p-n junctions. The technique is reversible, such that the dopant atoms introduced into the graphene can be removed while preserving the original graphene band structure.